Elements of conchology Prepared Elements of conchology / Prepared for the use of schools and colleges elementsofconcho00rusc Year: 1844 LINGULA TEREBRATULA. 89 Fig. 111. TEREBRATUL,A. and a bivalve shell; they have no foot, but in place of it, two fleshy arms furnished with filaments, and susceptible of being un- folded externally, or drawn within the shell by folding spirally (Jig. HI, a); their branchise are not distinct from the mantle, and the mass formed by their viscera is very small. They are unprovided with organs of locomotion, and live attached to submarine bodies. The principal
Elements of conchology Prepared Elements of conchology / Prepared for the use of schools and colleges elementsofconcho00rusc Year: 1844 LINGULA TEREBRATULA. 89 Fig. 111. TEREBRATUL,A. and a bivalve shell; they have no foot, but in place of it, two fleshy arms furnished with filaments, and susceptible of being un- folded externally, or drawn within the shell by folding spirally (Jig. HI, a); their branchise are not distinct from the mantle, and the mass formed by their viscera is very small. They are unprovided with organs of locomotion, and live attached to submarine bodies. The principal genera composing this group, are the Lingula, Terebratula, and Orbicula. 23. The Lingula are provided with a long fleshy peduncle, one extremity of which is generally attached to the rocks these animals ordinarily inhabit, and the other is furnished with two oblong, flattened valves. Their arms, which are inserted in the sides of the mouth, are very long ; and the branchial vessels are distributed on the internal face of the mantle, and there form on each side a series of small parallel folds. They are found in the Asiatic Seas. 24. The have two unequal valves joined by a hinge, and one of them (f,g. 112) has a hole through its summit .for the pas- sage of a fleshy peduncle, by means of which the animal attaches itself. Their branchife are less distinct than in the Lingula3, and consist simply of a vascular net-work spread over the internal face of the mantle; but their muscular system is more de- veloped, and there is found in the interior of the shell a small solid frame (Jig. 113), the structure of which is sometimes very compli- cated; its chief uses are to afford attachment to muscles, and to as- sist in separating the valves. Some living Terebratulse are found in the South Seas; but they abound most in the fossil state; and are
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